The cogency monitor: an external interface architecture for a distributed object-oriented real-time database system

The authors are developing a distributed database, called BeeHive, which could offer features along different types of requirements: real-time, fault-tolerance, security and quality-of-service for audio and video. Support of these features and potential trade-offs between them could provide a significant improvement in performance and functionality over current distributed database and object management systems. The BeeHive system however must be able to interact with existing databases and import such data. They present a high level design for this external interface and introduce the concept of a cogency monitor which acts as a gateway between BeeHive and the external world. The cogency monitor filters, shapes, and controls the flow of information to guarantee specified properties along the real-time, fault tolerance, quality of service, and security dimensions. They also describe three implementations of the cogency monitor and present some preliminary performance results that demonstrate the value of the cogency monitor.